The present invention relates generally to thin provisioning and tier management and, more particularly, to a method and an apparatus to save and restore tier information.
In recent years, thin provisioning has become popular. Thin provisioning is a method for allocating area for a storage subsystem that receives a write command to unallocated area. Currently, a storage subsystem migrates frequently accessed allocated area to fast and expensive media and migrates rarely accessed allocated area to slow and cheap media. As such, an area accessed by a program that runs only at specified times is not accessed and is moved to slow media when the program does not run. However, a problem with performance will occur when the program starts.